First things first what type router do you have? With most routers you can type 192.168.1.1 in your browser and get router information. You can do an Internet search and get the default user name and password to get to diagnostic page. What OS are you using is important as well. Please supply this information Router Type and OS first then maybe we can help.
I am having problems with my router will not accept my password. I'm tethered to my phone to send this post. My equipment was installed 2/11/16 I have problems in the past and was helped by posting on this forum. Hopefully I can receive much needed help again. Called tech support and was put on hold for about an hour and told to schedule a service call by someone named Charles. Once again no other advice was given. My equipment should be under warranty I hope so. Once again I hope this post gives me some answers. Looking forward to your reply
Thanks for posting. Whats the make and model? Usually you there is a reset button accessible by a small pin to reset the password to the default. Which is located on the sticker. Let me know if this helps.